Wherever did Leonard get the musical inspiration for Tacoma Trailer, the instrumental cut on The Future? The Jazz Police have discovered a clue. It may be stolen from a 1968 piece by Yusef Lateef
Listen to this beautiful piece, especially 5:59 onward. Sound familiar?

Some clarification on that source firstly from "The Source Himself" during an Interview in 1992 "The Future Radio Special" from a special CD released by Sony music.

LC’s words:
"This was designed for a theatre piece by Ted Allen. It was part of long suite and I kept playing the music when I was in this trailer in Tacoma. That part of the suite attached itself and started to sound better and better. Then, I thought it would just be a nice moment to unwind from a very dense and literate album. I think you can unwind before you put the record on again."

Some technical aspects of “Tacoma Trailer” include that it is written in a 4/4 meter, in the key of D flat major, and its playing instructions are cantabile e legato. One of LC’s signature songwriting styles is the presence of minor chords. From a songwriting standpoint, LC has said, “I think the juxtaposition of a major chord with no seventh going into a minor chord is a nice feel. I like that feel.” With that in mind, “Tacoma Trailer” contains a friendly mixture of major and minor chords.

The personnel on this recording were Leanne Ungar (engineer), Steve Croes (synthesizer), and Bill Ginn (producer).
LC wrote and arranged the song.

Incidentally “Helen’s Theme (Incidental Music)” on a Columbia Records promotional cassette tape copyright 1992 Sony Music Entertainment Inc was an early, shorter four minutes long piece that later became “Tacoma Trailer.”